Line cook Lucas Higgins at Mexican restaurant Zapoteca, an eatery that has enjoyed success since its opening almost three years ago. Owner and Executive Chef Shannon Bard was even featured in an episode of the Food Network's Beat Bobby Flay that will air this spring.

As the annual Maine Restaurant Week progresses, you may notice that among the old faces, there are a slew of brand new eateries, and a handful of others that you remember from just last year have disappeared.

According to Professor Charles Colgan of public policy and management and the Muskie School of Public Service and long-time former chair of the State of Maine Consensus Economic Forecasting Commission, there’s nothing unusual about that. “Restaurants are the same pretty much everywhere. They are the business most frequently started and most frequently closed.”

Greg Dugal, executive director and CEO of the Maine Restaurant Association and Maine Innkeepers Association, had a few ideas about why that is. “Primarily, in this day and age, food is not the question,” Dugal said. “Most everybody knows how to cook.”

A common problem, he said, is that often chefs open restaurants, and they come into the business with more knowledge about the kitchen than the front of the house. Poorly trained servers, managers, bartenders and other front-of-the-house staff who don’t know the menu or don’t treat guests courteously, Dugal said, can break a fledgling restaurant, no matter how good the food is.

Leigh Kellis, owner of Portland’s The Holy Donut, has owned and operated her donut shop for almost two years, and this October, she opened up a second location on Exchange street. She came into the foodservice industry with more experience at the front of the house than in the kitchen. Kellis had worked as a bartender and a server before opening The Holy Donut when she started experimenting with donut recipes. “I was working at Otto’s Pizza, and that summer, I craved donuts, and Otto’s owner said ‘You should open a donut shop.’”

Kellis, who does $3,000 worth of business a day, can speak to what it means to run a successful Portland food establishment. She attributes the success of The Holy Donut to her staff, of whom there are now 24 between the two locations, as well as to having a product she is passionate about and sticking to her ideals of making healthy food with local ingredients.

“My philosophy is that I wouldn’t sell anything that I wouldn’t feed to my daughters,” Kellis said.

Another issue Dugal said many restaurants face is the relatively low profit margin for each individual plate of food. “Profit margins are pretty small, if you’re good you can make 10 percent,” Dugal said. There are a lot of people involved in keeping a restaurant running, which keeps the profit margin for restaurants low.

The best way to combat this issue, Dugal said, is to keep portions regular and keep costs down. Those with business experience rather than culinary experience, Dugal said, are more likely to have effective plans for how to keep costs low and profits high.

Shannon and Tom Bard, the husband and wife team who co-owner and operate Zapoteca, a high-end Mexican restaurant with a focus on Oaxacan recipes and ingredients located on 505 Fore Street, together balance managerial and culinary experience. Shannon Bard studied Oaxacan cooking at the Culinary Institute of America and recently filmed an episode of Bobby Flay’s Dinner Battle, which will air some time in March, while Tom Bard has been in the industry for 40 years and brings a strong managerial foundation.

Shannon Bard described her thoughts about the Portland restaurant scene during a recent trip to New York City. “There’s nothing they were doing there that we’re not already doing here [in Portland] … We’re all just competitive and want to be the best at what we do,” she said.

Colgan and Dugal agreed that simple lack of sufficient funding can bring a restaurant down. “Restaurants tend to be under-capitalized for the hyper-competitive market of food, especially in a foodie town like Portland,” Colgan said, while Dugal cited high rent, utilities, insurance and payments on loans to cover start-up costs, that could eat too far into profit margins for a restaurant to stay afloat.

Kellis expressed gratitude for The Holy Donut’s strong local following and said that she believes the affordable price at which she can both make and sell donuts is a strong contributing factor to her success. “It’s a cheap thrill, as I like to say,” Kellis said.

“Portland’s restaurant scene is often described as ‘vibrant,’ but that is just a more optimistic description of the tumult that is the native characteristic of most urban restaurants,” Colgan said, so this Restaurant Week, be sure to check out your favorites while they’re hot.